Highly read on http://www.cell.com in November

Certain targeted cancer drugs shrink tumours by shutting down key genes. But researchers report that this may not be enough to vanquish cancer — a functional immune system is also a pre-requisite.

Immune cells are known to be important in restricting tumour formation, but less is known about their role in tumour regression. Dean Felsher at Stanford University in California and his team switched off genes required for tumour growth in mouse models of lymphoma and leukaemia. They found that the rate of tumour shrinkage fell when the mice lacked an intact immune system — to up to one-thousandth of the normal speed — and the frequency of tumour recurrence rose.

The team discovered that immune cells called CD4+ T cells are needed to shut down blood-vessel growth and to trigger tumour-cell senescence. Moreover, a protein produced by the T cells called thrombospondin 1, which blocks blood-vessel formation, seems to be key to fending off tumours.

Cancer Cell 18, 485–498 (2010)